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Additional file 1 TableS1. The list of RT-qPCR primers used in this study. Fig.S1Acquisition of SARS-CoV-2 mouse-adapted strain BMA8. Fig.S2The effects of BMA8 strain on pathogenicity of infected mice. Fig.S3 The NP expression in lung tissues of infected mice. Fig. S4 The effects of BMA8 strain infection on the expression of inflammation-related genes in lung tissues of C57BL/6N and BALB/c mice at 0 dpi and 3 dpi, including Ifnb1, Cxcl10, Ccl2, Il6, Tnf, Ifit3, Irf7, Gbp5 and Isg15. Fig. S5 The expression levels of ACE2 protein in lung and kidney tissues of C57BL/6N and BALB/c mice; β-actin was used as a loading control. Fig. S6 Effects of H-2Kb mAbs on body weight and survival rate of mice infected with BMA8 strain. Fig. S7 Effects of H-2Kb mAbs on pathogenicity of BMA8 strain in C57BL/6N mice. Fig. S8 The expression of NP in lung tissues of infected mice. Fig. S9 The effects of BMA8 strain infection on the expression of inflammation-related genes in lung tissues of C57BL/6N and BALB/c mice with or without H-2Kb mAbs treatment, including Ifnb1, Cxcl9, Cxcl10, Ccl2, Ccl3, Ccl5, Il6, Tnf, Ifit3, Mx1 and Irf7.

Polysaccharides from Pleurotus eryngii exhibit a variety of biological activities. Here, we obtained a homogeneous branched β-1,6-glucan (APEP-A-b) from the fruiting bodies of P. eryngii and investigated its effect on immunity and gut microbiota. Our results showed that APEP-A-b significantly increases splenic lymphocyte proliferation, NK cell activity and phagocytic capacity of peritoneal cavity phagocytes. Furthermore, we found that the proportion of CD4+ and CD8+ T cells in lamina propria are significantly increased upon APEP-A-b treatment. Additionally, APEP-A-b supplementation demonstrated pronounced changes in microbiota reflected in promotion of relative abundances of species in the Lachnospiraceae and Rikenellaceae families. Consistently, APEP-A-b significantly increased the concentration of acetic and butyric acid in cecum contents. Overall, our results suggest that β-1,6-glucan from P. eryngii might enhance immunity by modulating microbiota. These results are important for the processing and product development of P. eryngii derived polysaccharides.

During pregnancy, placental protein-13 (galectin-13) is highly expressed in the placenta and fetal tissue, and less so in maternal serum that is related to pre-eclampsia. To understand galectin-13 function at the molecular level, we solved its crystal structure and discovered that its dimer is stabilized by two disulfide bridges between Cys136 and Cys138 and six hydrogen bonds involving Val135, Val137, and Gln139. Native PAGE and gel filtration demonstrate that this is not a crystallization artifact because dimers also form in solution. Our biochemical studies indicate that galectin-13 ligand binding specificity is different from that of other galectins in that it does not bind β-galactosides. This is partly explained by the presence of Arg53 rather than His53 at the bottom of the carbohydrate binding site in a position that is crucial for interactions with β-galactosides. Mutating Arg53 to histidine does not re-establish normal β-galactoside binding, but rather traps cryoprotectant glycerol molecules within the ligand binding site in crystals of the R53H mutant. Moreover, unlike most other galectins, we also found that GFP-tagged galectin-13 is localized within the nucleus of HeLa and 293 T cells. Overall, galectin-13 appears to be a new type of prototype galectin with distinct properties.

Cannabinoids and related drugs generate profound behavioral effects (such as analgesic effects) through activating CNR1 (cannabinoid receptor 1 [brain]). However, repeated cannabinoid administration triggers lysosomal degradation of the receptor and rapid development of drug tolerance, limiting the medical use of marijuana in chronic diseases. The pathogenic mechanisms of cannabinoid tolerance are not fully understood, and little is known about its prevention. Here we show that a protein involved in macroautophagy/autophagy (a conserved lysosomal degradation pathway), BECN2 (beclin 2), mediates cannabinoid tolerance by preventing CNR1 recycling and resensitization after prolonged agonist exposure, and deletion of Becn2 rescues CNR1 activity in mouse brain and conveys resistance to analgesic tolerance to chronic cannabinoids. To target BECN2 therapeutically, we established a competitive recruitment model of BECN2 and identified novel synthetic, natural or physiological stimuli of autophagy that sequester BECN2 from its binding with GPRASP1, a receptor protein for CNR1 degradation. Co-administration of these autophagy inducers effectively restores the level and signaling of brain CNR1 and protects mice from developing tolerance to repeated cannabinoid usage. Overall, our findings demonstrate the functional link among autophagy, receptor signaling and animal behavior regulated by psychoactive drugs, and develop a new strategy to prevent tolerance and improve medical efficacy of cannabinoids by modulating the BECN2 interactome and autophagy activity.

Ginsenoside Rg2 is one of the major active components of ginseng and has many biological activities. This study aimed to investigate the protective effects of ginsenoside Rg2 against H2O2-induced injury and apoptosis in H9c2 cells. The results showed that pretreatment with ginsenoside Rg2 not only increased cell viability, but also decreased lactate dehydrogenase (LDH) release. Ginsenoside Rg2 inhibited the decrease of SOD, GSH-PX activities and the increase of MDA content induced by H2O2. Meanwhile, the levels of ROS generation and cardiomyocyte apoptosis in ginsenoside Rg2 group significantly reduced when compared with the model group. Western blot analyses demonstrated that ginsenoside Rg2 up-regulate level of Bcl-2 expression and down-regulate levels of Bax, Caspase-3, -9 expression. These findings indicated that ginsenoside Rg2 could protect H9c2 cells against H2O2-induced injury through its actions of anti-oxidant and anti-apoptosis.